I. Field of the Invention
The present invention relates generally to the field of heating devices for heating water and more particularly to the provision of a heating device which is electrically controlled and heats water instantaneously on a demand basis immediately prior to the time the water is to be used.
II. Description of the Prior Art
In conventional devices for heating water there is normally provided a large storage tank of some 40-60 gallons in which water is stored after it has been heated, normally by electric or natural gas means. The storage tanks are usually sized to store all of the hot water that a consumer would normally demand in any given period of time. Because of the stand-by storage of the standard water tank, even the best insulated tank can lose as much as 20% or more of the heat necessary to keep a constant water temperature. Assuming that the water is to be used on a rather intermittent basis, the cost of keeping the water at a continuous temperature is extremely high with regard to a specific amount of water that is to be utilized.
Therefore, a conventional water heating system is inefficient when utilized for intermittent use. Logically speaking, intermittent use might even be considered in the normal household environment since frequently, water is used most frequently on a demand-basis during the morning and evening peak hours.
In the prior art, there have been instantaneous-type water heaters developed to heat the water immediately prior to its use. Typically, these "in-line heaters" supply water at a rather limited flow rate and that water is heated by methods which have been notoriously inefficient, thereby limiting the applicability of the instantaneous-type water heaters.